Atlas Obscura (via Daring Fireball) The Macaroni in 'Yankee Doodle' is Not What You Think .
On returning from a Grand Tour (a then-standard trip across Continental Europe intended to deepen cultural knowledge), these young men brought to England a stylish sense of fashion consisting of large wigs and slim clothing as well as a penchant for the then-little-known Italian dish for which they were named. In England at large, the word ‘macaroni’ took on a larger significance. To be ‘macaroni’ was to be sophisticated, upper class, and worldly.
In ‘Yankee Doodle,’ then, the British were mocking what they perceived as the Americans’ lack of class. The first verse is satirical because a doodle—a simpleton—thinks that he can be macaroni—fashionable—simply by sticking a feather in his cap. In other words, he is out of touch with high society."